Parabola and the complex solutions

In the next file you will find a prototype work of mine about complex solutions of a parabolic equation.


This work have been published in Greek language on at 2/May/2017

The license is Creative Commons and it is mentioned in the pdf… When I published that pdf, I had never see similar work… but I found many similar works after publishing. So, I don’t know if someone have gained the copyright of such work and if I have to mention his work in my pdf (and this means that my license has no value. If someone thinks that I have to change the license or that I have to mention his “previous work”… I am open to discuss it.)